skip navigation
New Hampshire Department of Environmental Services

Frequently Asked Questions

Chemical Sampling Guidance

This guidance is for water system owners, operators and sampling agents with specific questions on Chemical Monitoring sampling, and does NOT list the many other requirements required by these rules. Please refer to the additional information links and contacts at the end of this fact sheet for other questions and compliance requirements.

  • What are the components of the chemical monitoring schedule?

    The Master Sampling Schedule contains an up-to-date chemical schedule and can be found on the NHDES One Stop Data. It will list your routine sampling location(s) and the frequency of chemical sampling required for your system. There are six categories of contaminants:

    • VOC - Volatile Organic Compounds – annual (unless a sampling waiver is in place)
    • SOC - Synthetic Organic Compounds – annual (unless a sampling waiver is in place)
    • IOC - Inorganic Compounds – once every 3 years
    • Radionuclide (Compliance Gross Alpha, Uranium, and Radium 226 & 228) – frequency dependent on existing levels.
    • *Nitrate - Annual
    • *Nitrite - once every 3 years

      (*The only chemical monitoring required of Transient Public Water Systems)

Back to Top
  • What are my site ID number and sampling location?
    The “site ID” is a number designated by the Chemical Program to identify the proper sampling point for chemical monitoring. The “sampling location” further defines the proper sampling point for chemical monitoring. You should collect chemical samples at sample tap(s) prior to entry to the distribution system as determined by the system and/or DWGB surveyor. All chemical sampling locations should be representative of what the consumers are drinking. The site ID and sampling location are found on the Master Sampling Schedule.
Back to Top
  • How do I change my chemical sampling site?
    You should always submit a site change request BEFORE you take your routine chemical sample(s). This will ensure that DWGB has the newly updated sampling site in our database and will be able to accept the sample results. You may submit a site change request form found on our website (Sample Site Change Request FormMicrosoft Word Symbol). DWGB will review the requested site change and notify you when the change has been made.
Back to Top
  • How do I code my sample (e.g., RT, CF, MU) and what do these categories mean?
    You must always check the appropriate box on your analysis request form in order for the sample results to be credited properly for your system’s schedule.
    • RT = Routine scheduled sample
    • CF = Confirmation sample. Your system had a detection of a regulated contaminant and the DWGB has requested another sample for that specific contaminant. Further correspondences from the DWGB will outline any future requirements.
    • MU = Make-Up. A scheduled sample was not taken. The system will receive a Monitoring and Reporting Violation (M/R) which then requires the sample to be made up.
Back to Top
  • Why did I receive a reminder email?

If you are an Owner, Operator or Primary Contact with an email address in our database you will receive an email notification in the middle of your scheduled sampling period as a reminder to collect your samples. If you have already sampled, please check with the DWGB regarding the status of the sampling results.

Email reminders are also sent if we have not received scheduled chemical sample results a week from the end of the sampling period.

Back to Top
  • How can get my sample bottles? Can they be mailed?
    You can order sample bottles on line at the One Stop site or phone the state laboratory at 271-3445. You can also query the accredited laboratories to find out which labs are accredited to analyze the samples you are required to take. Links for these two websites can be found at the bottom of this FAQ page.
Back to Top
  • How do I apply for a reduction in chemical sampling?
    If your system has been placed on quarterly monitoring for a contaminant or contaminant group, you must collect at least 4 quarters of samples before a reduction can be requested. If the concentration of the contaminant(s) meets the established threshold, and you have not installed treatment to lower levels of that contaminant or contaminant group, you may request a sampling reduction by contacting our office in writing and submitting sampling results for the last 4 quarters. The DWGB will review your request and will contact you in writing of the decision.
Back to Top
  • How do I apply for a VOC and/or SOC sampling waiver?
    You may contact the Waiver Program at (603) 271-2862 to obtain information regarding VOC and/or SOC sampling waivers. See the link at the bottom of this FAQ page for more information.
Back to Top
  • What is an MCL?
    MCL stands for Maximum Contaminant Level. MCLs are health based standards and are the maximum permissible levels of contaminants which can be present in the water which is consumed by any customer of a public water system. For most chemical contaminants, compliance with an MCL is based on an average of sampling result values, called the Running Annual Average (RAA).
Back to Top
  • How do I calculate the Running Annual Average (“RAA”)?
    The running annual average is the average of results for all routine samples taken over the past year. This is calculated individually for most chemical contaminants and determines compliance with the applicable MCLs for regulated contaminants.
Back to Top
  • What Sampling Form should I use to troubleshoot system problems or check to determine that my treatment is working properly?
    Use the General System Evaluation Sample form found at the bottom of your Master Sampling Schedule and code the samples as “treatment evaluations.” See the GSES FAQ page for more information.
Back to Top
  • Why do I have to provide Public Notice to the water system customers?
    Public Notification provides a mechanism for public water systems to keep their customers informed of drinking water violations or situations that may affect public health and is required by both Federal and State regulations.
Back to Top
  • How do I provide Public Notice to the water system customers?
    Each public notice form contains directions about how to issue the notice. If using the public notice template provided by DWGB, be sure to fill out each section completely, including the Certification page. The notice must be distributed according to the type of system you serve and both pages must be submitted to DWGB.

    All public notice templates can be found on the Public Notice Forms page of our website. The information that you will need in order to properly fill out the forms can be found in your records, on the recent letter that you received, or you can contact the person that sent you the letter to aid you in the process of filling out the entire notice completely and correctly.

Back to Top
  • We have taken compliance samples after our scheduled compliance period ended. Do we still need to provide public notice to the water system customers?
    This depends on the contaminant or contaminant group that was sampled late. A Notice of Violation (NOV) will be sent to system representatives detailing the corrective actions that need to be taken and will note the public notice requirement if applicable. The public notice will tell your customers that the system failed to sample within the designated compliance period. The notice will also tell customers the date that you sampled on.
Back to Top
  • Can I find sampling results on the One Stop website?
    Yes, results for chemical monitoring samples can be found on the NHDES One Stop Data site. In the future, when all private laboratories are able to submit their results electronically, we intend to have results from the private labs also on the website
Back to Top
Back to Top



Adobe Acrobat Reader Symbol Adobe Acrobat Reader format. Download a free reader from Adobe.

Microsoft Word SymbolMicrosoft Word format: free viewer instructions from Microsoft.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

copyright 2017. State of New Hampshire